Rionegro, Colombia

Catholic University of the East

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Rionegro, Colombia
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Granados D.A.,National University of Colombia | Granados D.A.,Catholic University of the East | Ruiz R.A.,National University of Colombia | Vega L.Y.,National University of Colombia | Chejne F.,National University of Colombia
Energy | Year: 2017

A complete study of torrefaction process to sugarcane bagasse under different thermal conditions was developed. After torrefaction process, chars were burned in an oxidizing atmosphere and its reactivities were studied. The torrefied biomass was characterized through chemical and physical analysis such as proximate and elemental analyses, lignocellulosic composition, High Heating Value (HHV), Fourier Transform Infrared Spectroscopy (FTIR) and observations in Scanning Electron Microscopy (SEM). The torrefied biomass was also evaluated in oxidizing conditions in order to analyze the impact of torrefaction process over biomass combustion process. Remarkable changes of the main functional groups were observed as the severity of the torrefaction process increased. The main structural carbohydrates affected in the process were hemicellulose and cellulose, which break down largely as a result of decarboxylation reactions, and breakage of links with methyl and acetyl groups. This was evidenced qualitatively when the material was observed in SEM, an increase in the decomposition of the cell wall structures as the process temperature increased was noted. These changes in the material were also verified with FTIR tests, and lignified matrix with higher content of aromatic groups and greater thermal stability is yielded with temperature increases. © 2017 Elsevier Ltd


Garzon J.,Catholic University of the East | Pavon J.,Complutense University of Madrid | Baldiris S.,Complutense University of Madrid
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2017

Augmented Reality (AR) systems have reached certain level of maturity in educational environments and their effectiveness has been widely proven. There are many literature review studies that have determined the trends, affordances and challenges of this emerging technology in educational settings. However, these studies do not propose practical solutions that aim to solve the challenges and issues found in AR systems. There are still some problems that need to be addressed in order to obtain the best of this technology and ensure the most appropriate integration of AR into education. There are still unexplored fields of application in which AR systems can help expand the possibilities and improve learning processes. This paper, proposes five directions for future research around possible solutions for some of the most important challenges of AR applications for education. These proposals are based on the findings of a literature review of 50 studies published between 2011 and 2017 in scientific journals. As a result, we provide a guideline for developers and practitioners to continue to expand the accurate integration of AR systems into educational environments. © Springer International Publishing AG 2017.


Cortes N.,University of Antioquia | Mora C.,University of Antioquia | Munoz K.,University of Antioquia | Diaz J.,Catholic University of the East | And 3 more authors.
Brazilian Journal of Pharmacognosy | Year: 2014

Taraxacum officinale F. H. Wigg, Asteraceae, is frequently misidentified or substituted with Hypochaeris radicata L., Asteraceae (false dandelion). To increase our knowledge of T. officinale and differentiate it from H. radicata, we investigated the two species using a combination of taxonomy, microscopy, and chromatographic studies via fingerprint profiles. Micromorphological characteristics were studied using scanning electron microscopy, while optic light microscopy was used for histochemical observations. Fingerprint profiles were constructed using HPTLC. T. officinale was found to have a morphologically distinct type of pluricellular trichomes that can be used to differentiate the two species, as these structures were not identified in H. radicata samples. Furthermore, two types of laticiferous vessels may also be distinctive characteristics of T. officinale at species level. In addition, the HPTLC data derived from methanolic extracts of H. radicata and T. officinale roots showed clearly different chemical profiles. Thus this study establishes the authenticity of T. officinale, and the observed parameters could help minimize drug substitutions in herbal medicines. © 2014 Sociedade Brasileira de Farmacognosia. Published by Elsevier Editora Ltda. All rights reserved.


Rios-Pulgarin M.I.,Catholic University of the East | Rios-Pulgarin M.I.,National University of Colombia | Barletta M.,Catholic University of the East | Barletta M.,Federal University of Pernambuco | Mancera-Rodriguez N.J.,National University of Colombia
Journal of Fish Biology | Year: 2016

The seasonal and interannual changes of the fish assemblage in the main channel and littoral zone of the Guarinó River, a torrential system located in the Colombian Andean foothills, were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle and the El Niño–La Niña–Southern Oscillation (ENSO) between 2007 and 2010. Four samplings per year (in dry season and high water) were performed. Environmental variables (temperature, pH, conductivity, turbidity, oxygen, total nitrogen, orthophosphate, depth and flow rate) were contrasted with ANOVAs and a discriminant analysis to establish temporal patterns. Biological descriptors (richness, density and biomass) were contrasted with ANCOVAs. The temporal patterns of the taxonomic and functional composition and the density of the fish assemblages were examined with respect to environmental variables through canonical discriminant analysis per habitat. Interannual differences were significant with regard to density and richness for the main channel habitat; while in the littoral zone, the differences were significant between both the year and seasons. Discriminant analysis showed variations in species composition and relative abundance between the main channel and the littoral zone under contrasting hydrological conditions of El Niño–La Niña. High flows from 2008 to 2009 (La Niña) favoured resident species (e.g. Creagrutus magdalenae) and small benthic Siluriformes (e.g. Chaetostoma spp.), but was limited to migratory species (e.g. Prochilodus magdalenae). From 2009 to 2010 (El Niño), the most common species were reduced and rare species increased. River flow, temperature and oxygen were the variables that had the largest influences on the seasonal and interannual differences in the fish assemblage structure of the Guarinó River. The results suggested that the presence and abundance of species and functional groups in different habitats were regulated by stochastic conditions, such as droughts, floods and drag events associated with the Southern Oscillation phenomenon (ENSO), acting as a hydrological disturbance on the habitats and generating different responses according to the adaptive characteristics of the species. © 2015 The Fisheries Society of the British Isles


Rios-Pulgarin M.I.,Catholic University of the East | Barletta M.,Federal University of Pernambuco | Mancera-Rodriguez N.J.,National University of Colombia
Journal of Fish Biology | Year: 2015

The seasonal and interannual changes of the fish assemblage in the main channel and littoral zone of the Guarinó River, a torrential system located in the Colombian Andean foothills, were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle and the El Niño-La Niña-Southern Oscillation (ENSO) between 2007 and 2010. Four samplings per year (in dry season and high water) were performed. Environmental variables (temperature, pH, conductivity, turbidity, oxygen, total nitrogen, orthophosphate, depth and flow rate) were contrasted with ANOVAs and a discriminant analysis to establish temporal patterns. Biological descriptors (richness, density and biomass) were contrasted with ANCOVAs. The temporal patterns of the taxonomic and functional composition and the density of the fish assemblages were examined with respect to environmental variables through canonical discriminant analysis per habitat. Interannual differences were significant with regard to density and richness for the main channel habitat; while in the littoral zone, the differences were significant between both the year and seasons. Discriminant analysis showed variations in species composition and relative abundance between the main channel and the littoral zone under contrasting hydrological conditions of El Niño-La Niña. High flows from 2008 to 2009 (La Niña) favoured resident species (e.g. Creagrutus magdalenae) and small benthic Siluriformes (e.g. Chaetostoma spp.), but was limited to migratory species (e.g. Prochilodus magdalenae). From 2009 to 2010 (El Niño), the most common species were reduced and rare species increased. River flow, temperature and oxygen were the variables that had the largest influences on the seasonal and interannual differences in the fish assemblage structure of the Guarinó River. The results suggested that the presence and abundance of species and functional groups in different habitats were regulated by stochastic conditions, such as droughts, floods and drag events associated with the Southern Oscillation phenomenon (ENSO), acting as a hydrological disturbance on the habitats and generating different responses according to the adaptive characteristics of the species. © 2015 The Fisheries Society of the British Isles.


PubMed | University of the Atlantic, Catholic University of the East, National University of Colombia, Fundacion Verdes Horizontes and 3 more.
Type: Journal Article | Journal: Journal of fish biology | Year: 2016

The remarkable fish diversity in the Caribbean rivers of north-western South America evolved under the influences of the dramatic environmental changes of neogene northern South America, including the Quechua Orogeny and Pleistocene climate oscillations. Although this region is not the richest in South America, endemism is very high. Fish assemblage structure is unique to each of the four aquatic systems identified (rivers, streams, floodplain lakes and reservoirs) and community dynamics are highly synchronized with the mono-modal or bi-modal flooding pulse of the rainy seasons. The highly seasonal multispecies fishery is based on migratory species. Freshwater fish conservation is a challenge for Colombian environmental institutions because the Caribbean trans-Andean basins are the focus of the economic development of Colombian society, so management measures must be directed to protect aquatic habitat and their connectivity. These two management strategies are the only way for helping fish species conservation and sustainable fisheries.


PubMed | CNRS Systematics, Biodiversity and Evolution Institute, National University of Colombia, Montpellier University, Catholic University of the East and 7 more.
Type: Journal Article | Journal: Molecular ecology | Year: 2016

Understanding why species richness peaks along the Andes is a fundamental question in the study of Neotropical biodiversity. Several biogeographic and diversification scenarios have been proposed in the literature, but there is confusion about the processes underlying each scenario, and assessing their relative contribution is not straightforward. Here, we propose to refine these scenarios into a framework which evaluates four evolutionary mechanisms: higher speciation rate in the Andes, lower extinction rates in the Andes, older colonization times and higher colonization rates of the Andes from adjacent areas. We apply this framework to a species-rich subtribe of Neotropical butterflies whose diversity peaks in the Andes, the Godyridina (Nymphalidae: Ithomiini). We generated a time-calibrated phylogeny of the Godyridina and fitted time-dependent diversification models. Using trait-dependent diversification models and ancestral state reconstruction methods we then compared different biogeographic scenarios. We found strong evidence that the rates of colonization into the Andes were higher than the other way round. Those colonizations and the subsequent local diversification at equal rates in the Andes and in non-Andean regions mechanically increased the species richness of Andean regions compared to that of non-Andean regions (species-attractor hypothesis). We also found support for increasing speciation rates associated with Andean lineages. Our work highlights the importance of the Andean slopes in repeatedly attracting non-Andean lineages, most likely as a result of the diversity of habitats and/or host plants. Applying this analytical framework to other clades will bring important insights into the evolutionary mechanisms underlying the most species-rich biodiversity hotspot on the planet.


Jaramillo-Villa U.,Catholic University of the East | Jaramillo-Villa U.,University of Antioquia | Jaramillo-Villa U.,Institute Investigacion Of Recursosbiologicos | Maldonado-Ocampo J.A.,Federal University of Rio de Janeiro | And 2 more authors.
Journal of Fish Biology | Year: 2010

This study documents differences in fish assemblages for 32 freshwater streams located between 258 and 2242 m a.s.l. on the eastern slopes of the central range of the Colombian Andes. A total of 2049 fishes belonging to 62 species, 34 genera and 16 families were collected. Species richness declined rapidly with altitude; nearly 90% of the species were recorded between 250 and 1250 m a.s.l. Three of the four physico-chemical variables, of the water, temperature, dissolved oxygen and pH, explained 53·5% of the variation in species richness along the altitudinal gradient, with temperature the most important (37·6%). An analysis of species composition showed that the distinctiveness of the fish fauna increased with elevation, with the greatest turnover observed between 1000 and 1750 m a.s.l. On this altitudinal gradient, turnover was dominated by the loss of species rather than gain, and dominance by just a few species was greater at higher elevations. Turnover was also observed along the altitudinal gradient in the structure of the three functional groups (torrential, pool and pelagic species). The study focused on understanding the pattern of diversity of fish communities inhabiting the Andes in Colombia. Anthropogenic effects on the altitudinal distribution of fish species in the region, however, are largely unknown and would require further investigations. © 2010 The Authors. Journal compilation © 2010 The Fisheries Society of the British Isles.


PubMed | Catholic University of the East and National University of Colombia
Type: Journal Article | Journal: Journal of fish biology | Year: 2016

The seasonal and interannual changes of the fish assemblage in the main channel and littoral zone of the Guarin River, a torrential system located in the Colombian Andean foothills, were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle and the El Nio-La Nia-Southern Oscillation (ENSO) between 2007 and 2010. Four samplings per year (in dry season and high water) were performed. Environmental variables (temperature, pH, conductivity, turbidity, oxygen, total nitrogen, orthophosphate, depth and flow rate) were contrasted with ANOVAs and a discriminant analysis to establish temporal patterns. Biological descriptors (richness, density and biomass) were contrasted with ANCOVAs. The temporal patterns of the taxonomic and functional composition and the density of the fish assemblages were examined with respect to environmental variables through canonical discriminant analysis per habitat. Interannual differences were significant with regard to density and richness for the main channel habitat; while in the littoral zone, the differences were significant between both the year and seasons. Discriminant analysis showed variations in species composition and relative abundance between the main channel and the littoral zone under contrasting hydrological conditions of El Nio-La Nia. High flows from 2008 to 2009 (La Nia) favoured resident species (e.g. Creagrutus magdalenae) and small benthic Siluriformes (e.g. Chaetostoma spp.), but was limited to migratory species (e.g. Prochilodus magdalenae). From 2009 to 2010 (El Nio), the most common species were reduced and rare species increased. River flow, temperature and oxygen were the variables that had the largest influences on the seasonal and interannual differences in the fish assemblage structure of the Guarin River. The results suggested that the presence and abundance of species and functional groups in different habitats were regulated by stochastic conditions, such as droughts, floods and drag events associated with the Southern Oscillation phenomenon (ENSO), acting as a hydrological disturbance on the habitats and generating different responses according to the adaptive characteristics of the species.


PubMed | Catholic University of the East and National University of Colombia
Type: Journal Article | Journal: Journal of fish biology | Year: 2016

The seasonal and interannual changes in the fish, macroinvertebrates and phycoperiphyton assemblages of the Guarin River were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle and the El Nio-Nia/Southern Oscillation (ENSO) between 2007 and 2010. Four samplings (in dry and rainy seasons) were performed per year. Environmental variables (temperature, pH, conductivity, turbidity, oxygen, total nitrogen, orthophosphate, depth and flow rate) were measured. The temporal patterns of the taxonomic compositions for the three assemblages and the functional composition of fish and macroinvertebrate assemblages with respect to environmental variables were examined through canonical discriminant analysis, multidimensional scaling and multiple correlations. The presence and abundance of fishes, macroinvertebrates and algae species were regulated by environmental variables associated with extreme hydrological events, which derived from the natural torrential regimen of the basin and larger-scale phenomena, such as El Nio and La Nia. Fish abundance and richness were significantly correlated with algal density and pH, the macroinvertebrate density was negatively related to the flow rate and the richness was positively correlated with algal density. The algae richness was positively correlated with pH and negatively correlated with the flow rate and nitrogen. The algal density was positively correlated with pH and temperature and negatively correlated with river flow. The phycoperiphyton assemblage exhibited more direct responses in its density and richness to the hydrological changes (r(2) = 0743 and 0800, respectively). In functional terms, the El Nio phenomenon was defined by a greater abundance of omnivorous and insectivorous fishes, as well as filter feeders, scrapers and macroinvertebrate predators. During La Nia, a greater abundance of benthic fishes (both detritivorous and insectivorous) and shredder and collector-gatherer macroinvertebrates was observed. Differentiated responses recorded in the community were based on adaptive strategies for the local hydrological regime that enable fast recovery under conditions such as ENSO phenomena. Composition changes according to adaptations to different hydrological scenarios and the predominance of generalists trophic guilds and species with plasticity in their habits and their ranges of environmental tolerance were found, supporting the habitat templet model.

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